Over the past week or so I'm getting occasional screen freezes - at first it was while gaming (World of Warcraft), but I'm finding the same thing can occur when I'm only using a web browser (Firefox), without WoW running at all.
Today this happened while I was watching a Youtube video in Firefox, and I noticed that - while the screen was frozen and unresponsive (the video itself froze, cursor was there but with blue circle and nothing responded, couldn't ctrl+alt+del to get to task manager, etc.) - the sound from the video kept going. In the end, as with other freezes, I had to hard reset by holding down the PC's power button.
Does anyone have advice on what might be causing this? Maybe it's a hardware issue - graphics card perhaps, but I'm not sure how to diagnose it. I've made sure the drivers are up to date, and likewise with Windows updates. Haven't had any recent hardware changes at all.
Although I'm not getting a BSOD, I've run the diagnostic tool from that sub-forum, and zipped and uploaded the results here. Could someone possibly take a quick look and see if anything stands out, or give me some pointers on what to look for myself?